1. Field of the Invention
The present disclosure relates to a drive control device of a brushless DC motor.
2. Description of the Related Art
In the related art, there is known a drive control device for driving a brushless DC motor, which has function of stopping the motor for a safety purpose when an overcurrent is generated within the motor. The drive control device includes a current detection circuit arranged to detect a current value of a current flowing within the motor.
In the drive control device of the brushless DC motor, the current value detected by the current detection circuit is monitored by a microcomputer. Thus, when an overcurrent is generated within the motor, it is possible to take a measure of stopping the motor or other measures. In addition to the microcomputer, it is thinkable to provide a comparison circuit which compares the current value detected by the current detection circuit with a predetermined threshold value. If the comparison circuit is provided outside the microcomputer, it is possible to reduce the load borne by the microcomputer.
However, when an abnormality such as a short-circuit, an earth fault or an open state is generated in the comparison circuit, there is a possibility that it becomes impossible to detect the presence or absence of an overcurrent. For that reason, it is preferable to periodically self-diagnose whether the comparison circuit is normally operated.
There is a demand for a drive control device of a motor that can enjoy high stability while reducing the number of used terminals of a microcomputer.